Ground Truth Estimator

A first-principles cost estimator for Australian civil infrastructure projects, now a real multi-user product: sign-up/login, a shared rate library per company, unlimited projects, an itemised risk register, and a live weather/climate risk lookup.

Stack: Next.js 14 (App Router) + Supabase (Postgres + Auth) + Vercel (hosting).

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Before you start

This project was written in an environment with no access to the npm registry, so npm install has not been run here and the app has not been built or started locally yet. The code is complete and was syntax-checked with the TypeScript compiler, but the very first npm install you (or Vercel) run is also the first real compile. If that throws an error, paste it back to me and I'll fix it — nothing here has been guessed at a shape level, but a stray typo is always possible in a project this size written without a live build loop.

1. Create the Supabase project

1. Go to supabase.com, sign up (free), and create a new project. Pick a region close to your users (e.g. Sydney).
2. Once it's provisioned, open SQL Editor in the left sidebar → New query.
3. Paste in the entire contents of supabase/schema.sql from this project and click Run. This creates every table, security policy, and the trigger that gives each new signup their own workspace and starter rate library.
4. Go to Authentication → Providers → Email and confirm Email is enabled. For the fastest way to try this yourself, you can turn off "Confirm email" under Authentication → Settings while testing — turn it back on before giving real customers accounts.
5. Go to Project Settings → API. You'll need two values from this page in a moment: Project URL and the anon public key.

2. Run it locally (optional, but recommended before deploying)

npm install
cp .env.local.example .env.local
# edit .env.local and paste in your Supabase Project URL + anon key
npm run dev

Open http://localhost:3000, sign up, and you should land on an empty dashboard with a pre-seeded rate library. Click Load example project to see the full estimator working end to end.

3. Deploy to Vercel

1. Push this project to a new GitHub repository (Vercel deploys from git).
2. Go to vercel.com, sign up (free), and Add New → Project, then import that GitHub repo.
3. In the import screen, expand Environment Variables and add:
   • NEXT_PUBLIC_SUPABASE_URL = your Supabase Project URL
   • NEXT_PUBLIC_SUPABASE_ANON_KEY = your Supabase anon public key
4. Click Deploy. Vercel installs dependencies and builds the app on its own infrastructure — this is the first place the project will actually be compiled and run, since it wasn't possible in the sandbox that wrote it.
5. Once it's live, go to Authentication → URL Configuration in Supabase and add your new https://your-app.vercel.app URL as a Redirect URL (needed for the email confirmation link to come back to the right place).

4. Point your own domain at it

1. In your Vercel project, go to Settings → Domains and add the domain you registered (e.g. groundtruthestimator.com.au).
2. Vercel gives you either an A record or CNAME to add at your domain registrar (GoDaddy: DNS Management on the domain). Add it there.
3. Vercel issues an HTTPS certificate automatically once DNS propagates (usually minutes, occasionally longer).
4. Add the final domain to Supabase's Redirect URLs too (step 3.5 above), alongside the vercel.app one.

What's actually built

• Auth — email/password signup and login (app/login, app/signup), session refresh via middleware.ts, protected routes.
• Multi-tenancy — every signup gets its own organizations row; all data (rates, projects, categories, line items, risks) is scoped to that organization via Postgres Row Level Security, so one company can never see another's data. See supabase/schema.sql.
• Rate Library (app/dashboard/rates) — shared labour/plant/material rates for the whole company, editable inline, seeded with indicative Australian civil rates on signup. These are placeholders — replace them with your own supplier and subcontractor pricing.
• Projects & Estimate (app/dashboard/projects/[id]) — the original first-principles calculator (Earthworks, Roads & Pavements, Drainage, Structures), now backed by a real database instead of browser storage.
• Risk & Location — an itemised risk register (probability × cost impact, expected-value method) plus a weather-risk lookup backed by Open-Meteo (free, no API key): it geocodes the project location, pulls 5 years of historical daily climate data, and surfaces the wettest months, average hot days, and a rule-of-thumb tropical cyclone season flag (latitude-based — always cross-check the live Bureau of Meteorology outlook, this is a planning heuristic, not a forecast).
• Summary — the full cost cascade: Direct cost → Preliminaries → Risk allowance (from the register) → Contingency → Overhead → Margin → subtotal ex GST → GST → Contract price (what you'd tender), then Principal's administrative cost added separately to produce the Total project cost — since that line is the client's own cost, not part of your price.

Known limitations / good next steps

• No multi-member invites yet. The schema supports more than one user per organization (org_members), but there's no UI to invite a teammate — today, whoever signs up first is the only member. Worth adding before giving this to a whole team.
• No password reset flow. Supabase supports it; a "forgot password" page just hasn't been built yet.
• Weather lookup calls Open-Meteo on every click, with no caching. Fine for personal/small-team use; add a cache (e.g. a weather_cache table keyed by rounded lat/lon) if this gets heavy use.
• No billing. If you want this to be a paid product, Stripe + Vercel has a well-trodden integration path — ask me when you're ready for it.